//
// Verifies that mongos correctly handles empty documents when all fields are projected out
//

var options = {
    mongosOptions: {binVersion: ""},
    shardOptions: {binVersion: ""}
};

var st = new ShardingTest({shards: 2, other: options});

var mongos = st.s0;
var coll = mongos.getCollection("foo.bar");
var admin = mongos.getDB("admin");
var shards = mongos.getDB("config").shards.find().toArray();

assert.commandWorked(admin.runCommand({enableSharding: coll.getDB().getName()}));
printjson(admin.runCommand({movePrimary: coll.getDB().getName(), to: shards[0]._id}));
assert.commandWorked(admin.runCommand({shardCollection: coll.getFullName(), key: {_id: 1}}));

assert.commandWorked(admin.runCommand({split: coll.getFullName(), middle: {_id: 0}}));
assert.commandWorked(
    admin.runCommand({moveChunk: coll.getFullName(), find: {_id: 0}, to: shards[1]._id}));

st.printShardingStatus();

// Insert 100 documents, half of which have an extra field
for (var i = -50; i < 50; i++) {
    var doc = {};
    if (i >= 0)
        doc.positiveId = true;
    assert.writeOK(coll.insert(doc));
}

//
//
// Ensure projecting out all fields still returns the same number of documents
assert.eq(100, coll.find({}).itcount());
assert.eq(100, coll.find({}).sort({positiveId: 1}).itcount());
assert.eq(100, coll.find({}, {_id: 0, positiveId: 0}).itcount());
// Can't remove sort key from projection (SERVER-11877) but some documents will still be empty
assert.eq(100, coll.find({}, {_id: 0}).sort({positiveId: 1}).itcount());

//
//
// Ensure projecting out all fields still returns the same ordering of documents
var assertLast50Positive = function(sortedDocs) {
    assert.eq(100, sortedDocs.length);
    var positiveCount = 0;
    for (var i = 0; i < sortedDocs.length; ++i) {
        if (sortedDocs[i].positiveId) {
            positiveCount++;
        } else {
            // Make sure only the last set of documents have "positiveId" set
            assert.eq(positiveCount, 0);
        }
    }
    assert.eq(positiveCount, 50);
};

assertLast50Positive(coll.find({}).sort({positiveId: 1}).toArray());
assertLast50Positive(coll.find({}, {_id: 0}).sort({positiveId: 1}).toArray());

jsTest.log("DONE!");
st.stop();